1. Field of the Invention
This invention relates generally to dentistry and more particularly to a method of indicating points of contact between the interior of a prosthetic crown or the like and a prepared tooth, a die, an abutment or like mounting.
It is the practice when fitting a crown to a prepared tooth or die to position the crown to a point of resistance. Due to imperfections in the molding process involved in making impressions, there may be undesired protrusions and irregularities in the surface of the prosthetic crown confronting its mounting. Ideally, a crown should not be tight but should fit snugly and uniformly to its mounting. There is therefore needed a technique for indicating undesired protruding areas in the crown surfaces so that they can be eliminated.
2. Description of the Prior Art
Systems are known for identifying areas of voids between a crown and a mounting. For example, there exists a system wherein a paste, applied to either the mounting or the crown, is displaced by insertion of the crown onto the mounting. Areas of protrusion are indicated by the lack of a paste at areas of contact between the crown and its mounting.
Another system for identifying seating problems is marketed under the brand name "Liqua-Mark" Counter Indicator, which is a liquid system for identifying counter-seating problems and high occlusions between teeth. The composition of the material appears to be a slurry of a colored powder and a liquid. It has been found that it is somewhat messy, time consuming to use and inaccurate in its marking ability when used as a crown seating indicator. Moreover, it is not recommended for use in the mouth because of the danger of ingestion of toxic materials.
Another common technique for crown seating indication is the use of a graphite pencil wherein the graphite is applied directly to the prepared tooth or die, pressed into the crown and transferred upon contact to the, crown. This technique is also messy, and it tends to mark permanently and even damage the die.
What is needed is a method for indicating proper seating which is accurate, relatively clean, substantially non-toxic in the event of ingestion, and which does not cause damage.